AU2022302841A1

AU2022302841A1 - Method for preparing intermediate for synthesis of xanthine oxidase inhibitor

Info

Publication number: AU2022302841A1
Application number: AU2022302841A
Authority: AU
Inventors: Hui Rak JEONG; Ki Dae Kim; Ju Yeol Lee; Seok Ju Lee; Ah Byeol Park
Original assignee: LG Chem Ltd
Current assignee: LG Chem Ltd
Priority date: 2021-07-02
Filing date: 2022-07-01
Publication date: 2023-12-21
Also published as: CO2024001078A2; TW202308994A; WO2023277658A1; BR112023026062A2; CA3221122A1; MX2023014804A; CL2023003910A1; EP4349809A1; EP4349809A4; JP2024523604A; KR20230006408A; AR126353A1; US20240317685A1; TWI835186B; CN117561237A

Abstract

The present invention relates to a method for preparing an intermediate for synthesis of a xanthine oxidase inhibitor and, more specifically, to a method for preparing compounds of chemical formulas 2 and 4 by using low-priced starting materials and ligands and employing chelating extraction and purification techniques.

Description

DESCRIPTION TITLE OF INVENTION METHOD FOR PREPARING INTERMEDIATE FOR SYNTHESIS OF XANTHINE OXIDASE INHIBITOR TECHNICAL FIELD

The present invention relates to methods of preparing intermediates for

synthesizing xanthine oxidase inhibitor. More specifically, the present invention relates

to methods for preparing compounds of the following Formula 2 and Formula 4 by using

inexpensive starting materials and ligands, and a purification technique utilizing chelating

extraction:

[Formula 2] R1

X K\R2 R3

[Formula 4] R4

R5 R1 NN

R3

wherein, X is F, Cl, Br or I;

R1 is hydrogen or CN;

R2 is hydrogen, halogen, C1 -C 7 alkyl, C1 -C 7 alkoxy-C1-C7 alkyl or phenyl;

R3 is hydrogen; C1 -C 7 alkyl unsubstituted or substituted by one or more

substituents selected from halogen, C3-C 7 cycloalkyl and O-R6; C3-C 7 cycloalkyl; or

w R7 , wherein R6 is C 1-C 4 alkyl, W is 0 or S, R7 is hydrogen or C1 -C 4 alkyl,

and n is an integer of 0 to 3;

R4 is hydrogen, halogen or C1 -C 7 alkyl; and

R5 is -C(O)OR8, wherein R8 is hydrogen, C1 -C 7 alkyl or C3-C 7 cycloalkyl.

BACKGROUNDART

Xanthine oxidase is known as an enzyme which converts hypoxanthine to

xanthine and further converts thus-formed xanthine to uric acid. Although most

mammals have uricase, humans and chimpanzees do not, thereby uric acid is known to

be the final product of purine metabolism (S. P. Bruce, Ann. Pharm., 2006, 40, 2187

2194). Sustained elevation of blood concentration of uric acid causes various diseases,

representatively including gout.

As described above, gout is caused by an elevated level of uric acid in the body,

indicating the condition in which uric acid crystals accumulated in cartilage, ligament and

surrounding tissue induce severe inflammation and pain. Gout is a kind of inflammatory

articular disease, and its incidence rate has steadily increased during past 40 years (N. L.

Edwards, Arthritis & Rheumatism, 2008, 58, 2587-2590).

Accordingly, various studies have been conducted to develop new xanthine

oxidase inhibitors, and Korean Patent Application Publication No. 10-2011-0037883

discloses a novel compound of the following formula, which is effective as a xanthine

oxidase inhibitor:

0 A D

'N E Q

In Korean Patent Application Publication No. 10-2011-0037883 disclosing a

conventional preparation step of 5-bromo-3-cyano--isopropyl-indole-which is an

intermediate of the xanthine oxidase inhibitor, CsCO3-which is inconvenient to use due

to its low economic effectiveness and high density-was used, so that it was necessary to

secure a substitute for it. In addition, since there is no established purification method,

the organic layer obtained after the reaction and work-up process was concentrated and

the next reaction was carried out immediately. At this time, there was a problem in that

-bromo-3-cyano--isopropyl-indole included in the reaction mixture because it was not

purified acts as a causative material for generating impurity in the next reaction, adversely

affecting product quality.

Furthermore, the conventional preparation step for 1-(3-cyano--isopropyl

indol-5-yl)pyrazole-4-carboxylic acid ethyl ester has a very long reaction time of 35 to

48 hours, and the starting material, 5-bromo-3-cyano--isopropyl-indole, remains and

various impurities are generated. As a result, such materials can affect raw material

medicine, so that it was necessary to improve the quality and yield. In addition, after

completion of the reaction for 1-(3-cyano-1-isopropyl-indol-5-yl)pyrazole-4-carboxylic

acid ethyl ester, Na2SO 4 and silica gel were put into the reactor and then the adsorption

process was carried out to remove Cu-complex and in-organic by-products in the work

up process. At this time, there is an issue of cleaning the manufacturing equipment. In

addition, because filtration and washing to remove adsorbents and solid complexes lengthened the process time, and solid waste treatment was difficult, it is necessary to develop an effective purification method.

[Prior Document]

Patent Document: Korean Patent Application Publication No. 10-2011-0037883

DISCLOSURE OF INVENTION TECHNICAL PROBLEM

Accordingly, the technical problem of the present invention is the provision of

novel methods for preparing compounds of Formula 2 and Formula 4, which are key

intermediates in the synthesis of xanthine oxidase inhibitors, at a lower cost, effectively

reducing residual impurity, shortening reaction time, improving yield and eliminating the

possibility of generating solid waste:

[Formula 2]

R1

X K\R2

R3

[Formula 4]

R4

R5 RI Nj R2 NN

R3

wherein X, RI, R2, R3, R4 and R5 are the same as defined herein.

SOLUTION TO PROBLEM

To solve the above technical problem, there is provided a method for preparing a

compound of the following Formula 2, comprising:

i) a step of reacting a compound of Formula 1 and X-R3 with a base comprising

KOH in an organic solvent; and

ii) a step of crystallizing a product obtained in step (i) by using alcohol and an

anti-solvent comprising hydrocarbon having 5 to 8 carbon atoms:

[Formula 1]

R1

X1 N

H

[Formula 2]

R1

X K\R2 R3

wherein,

X is F, Cl, Br or I;

R1 is hydrogen or CN;

R2 is hydrogen, halogen, CI-C7 alkyl, C-C7 alkoxy-Ci-C7 alkyl or phenyl; and

R3 is hydrogen; C1 -C 7 alkyl unsubstituted or substituted by one or more

substituents selected from halogen, C 3 -C 7 cycloalkyl and O-R6; C 3 -C 7 cycloalkyl; or w

R7 , wherein R6 is C 1-C 4 alkyl, W is 0 or S, R7 is hydrogen or C 1 -C 4 alkyl,

and n is an integer of 0 to 3.

According to one embodiment of the present invention, X-R3 may be 2

iodopropane, but is not limited thereto.

According to one embodiment of the present invention, the organic solvent may

be acetone, but is not limited thereto.

According to one embodiment of the present invention, the alcohol may be one

or more selected from the group consisting of methanol, ethanol, propanol, isopropanol

and butanol, but is not limited thereto.

According to one embodiment of the present invention, the hydrocarbon having

to 8 carbon atoms may be selected from the group consisting of hexane, heptane and a

mixture thereof, but is not limited thereto.

According to one embodiment of the present invention, RI may be CN, R2 may

be hydrogen, and R3 may be isopropyl, but is not limited thereto.

According to another aspect of the present invention, there is provided a method

for preparing a compound of the following Formula 4, comprising:

a step of carrying out a C-N coupling reaction of a compound of Formula 2 and

a compound of Formula 3 with a copper catalyst, a base and a ligand comprising N,N

dimethylethylenediamine in an organic solvent:

[Formula 2]

R1 X

R3

[Formula 3]

R4 N NH

[Formula 4]

R4

R5 I R1 N

R3

wherein,

X is F, Cl, Br or I;

RI is hydrogen or CN;

R2 is hydrogen, halogen, C1 -C 7 alkyl, C1 -C 7 alkoxy-C1-C7 alkyl or phenyl;

R3 is hydrogen; C1 -C 7 alkyl unsubstituted or substituted by one or more

substituents selected from halogen, C 3 -C 7 cycloalkyl and O-R6; C 3 -C 7 cycloalkyl; or

W R7 , wherein R6 is CI-C4 alkyl, W is 0 or S, R7 is hydrogen or C1-C4 alkyl,

and n is an integer of 0 to 3;

R4 is hydrogen, halogen or C1 -C 7 alkyl; and

-7-.

R5 is -C(O)OR8, wherein R8 is hydrogen, C1 -C 7 alkyl or C3-C 7 cycloalkyl.

According to one embodiment of the present invention, the organic solvent may

be one or more selected from the group consisting of xylene, toluene, dimethylformamide

(DMF) and dimethyl sulfoxide (DMSO), but is not limited thereto.

According to one embodiment of the present invention, the copper catalyst may

be one or more selected from the group consisting of Cu, Cu(OAc)2, Cu, Cu20 and CuO,

but is not limited thereto.

According to one embodiment of the present invention, the base may be one or

more selected from the group consisting of potassium carbonate, cesium carbonate,

potassium phosphate tribasic, triethylamine and sodium tert-butoxide, but is not limited

thereto.

According to one embodiment of the present invention, the method for preparing

a compound of Formula 4 may further comprise a step of purifying the compound of

Formula 4 by using:

one or more chelating agents selected from the group consisting of EDTA, citric

acid, potassium citrate and sodium citrate; and

one or more ligand reagents selected from the group consisting of ammonium

chloride and aqueous ammonia, but is not limited thereto.

According to one embodiment of the present invention, RI may be CN, R2 may

be hydrogen, R3 may be isopropyl, R4 may be hydrogen, and R5 may be ethoxycarbonyl

(-C(O)OEt), but is not limited thereto.

EFFECTS OF THE INVENTION

The preparation method according to the present invention can secure economic effectiveness and effectively reduce residual impurity by replacing expensive Cs2CO3 with remarkably inexpensive KOH in the preparation of the compound of Formula 2. In addition, the preparation method according to the present invention dramatically shortens the reaction time in the preparation of the compound of Formula 4, and at the same time dramatically improves the yield compared to the conventional method and significantly reduces the possibility of generating solid waste, thereby making it easier to scale up.

BRIEF DESCRIPTION OF DRAWINGS

Figure 1 is a comparison of HPLC peak areas of residual 5-bromo-3-cyano-1H

indole before and after crystallization of5-bromo-3-cyano-1-isopropyl-indole. (GD40: 5

bromo-3-cyano-1H-indole, GD60: 5-bromo-3-cyano-1-isopropyl-indole)

Figure 2 represents the structures of the ligands subjected to the reaction of 1-(3

cyano-1-isopropyl-indol-5-yl)pyrazole-4-carboxylic acid ethyl ester.

Figure 3 represents the HPLC conversion ratio (%) of 5-bromo-3-cyano-1

isopropyl-indole into 1-(3-cyano-1-isopropyl-indol-5-yl)pyrazole-4-carboxylic acidethyl

ester.

Figure 4 represents the HPLC conversion ratio (%) of 5-bromo-3-cyano-1

ester.

Figure 5 represents the HPLC conversion ratio (%) of 5-bromo-3-cyano-1

isopropyl-indole into 1-(3-cyano-1-isopropyl-indol-5-yl)pyrazole-4-carboxylic acid ethyl

ester.

MODE FOR THE INVENTION

Hereinafter, the present invention is explained in more detail with the following

-9Q- examples. However, it must be understood that the protection scope of the present invention is not limited to the examples.

Example 1: Results of 5-bromo-3-cyano-1-isopropyl-indole reaction test

Example 1.1: Base screening of 5-bromo-3-cyano-1-isopropyl-indole

Cs2CO3, which is a raw material used for the synthesis of 5-bromo-3-cyano-1

isopropyl-indole in the previously known process, is quite expensive, and 1.7 equivalents

thereof in respect to 5-bromo-3-cyano-1H-indole were added to the reaction and

accounted for about 1% of the cost of raw materials. In addition, due to the high density

of Cs2CO3 (density: 4.07 g/cm 3 ), the agitation speed operation range was increased for

smooth stirring during the reaction. In order to solve such problems, 5-bromoindole was

first selected as an indole source and screening for various bases was carried out in the

following Reaction Scheme 1 (Table 1).

[Reaction Scheme 1]

Br 2-lodopropane Br

/~ N Solvent, Base N H Temperature Time 5-Bromo Indole Isopropylated Product

[Table 1] Isopropylation screening experiment of 5-bromoindole

Result (HPLC %ratio) Base Solvent Temp. Time Run 16 min 18 min 20 min 23 min (equiv) (fold) (°C) (h) (SM) (rt)

Example C23 52.5 8.6 2.1 36.6 1-1-1 (1.7) DMF 25 2.5 Example K2CO 3 (10) 96.2 3.6 0.2 1-1-2 (1.7)

Example STP 41.3 - 2.5 56.2 1-1-3 (1.7) Example NaGMe 50.2 - 1.3 48.5 1-1-4 (1.7) Example KOH 15.4 - 2.0 82.6 1-1-5 (1.7) Example CS2CO3 DMF 6.0 61.8 - 2.5 1-1-6 (1.7) (6) Example CS 2 CO3 59.2 - 2.3 38.5 1-1-7 (1.7) Example K23 74.0 0.7 1.1 24.1 1-1-8 (1.7) Example STP DMF 90 5.0 37.6 - 2.4 59.9 1-1-9 (1.7) (10) Example NaGMe 16.6 - 1.6 81.8 1-1-10 (1.7) Example KOH 16.0 - 1.9 81.9 1-1-11 (1.7) Example KOH 13.7 - 1.65 84.1 1-1-12 (2.0) Example KOH 8.3 - 1.7 90.0 1-1-13 (2.0) 35 3.5 Example KOH 14.0 0.8 1.1 83.8 1-1-14 (2.4) Example KOH DMF 1.45 1.1 0.6 96.9 1-1-15 (2.4) (10) Example NaGMe 53.1 1.9 2.1 42.9 1-1-16 (2.0) Example NaOMe 90 6.0 63.0 2.7 1.7 32.6 1-1-17 (2.0) Example NaGMe 54.0 - 2.2 43.8 1-1-18 (2.4)

STP: sodium tert-pentoxide

1.7 Equivalents of 2-iodopropane and DMF as the reaction solvent were selected,

and a suitable base in terms of the ratio of conversion to the alkylated product was predicted while changing the reaction temperature and reaction time. In Examples 1-1-1 to 1-1-5, KOH showed the highest conversion ratio. In the case of Examples 1-1-7 to

1-1-11, after raising the reaction temperature to 90°C, the reaction was performed. As

a result, the conversion ratio tendency of K2 C3 < Cs2CO3 < STP < NaOMe : KOH

can be known.

In Examples 1-1-12 to 1-1-18, the reaction temperature and equivalent were

changed in order to compare KOH and NaOMe. As a result, when KOH was used as a

base, the most desirable results were obtained. Based on the experiment in Table 1, an

isopropylation reaction was carried out in the following Reaction Scheme 2 using 5

bromo-3-cyano-H-indole in which CN group is substituted at the C3 position of 5

bromoindole (Table 2).

[Reaction Scheme 2]

CN CN Br 2-lodopropane Br

N Solvent, Base N H Temperature Time GD40 GD60

[Table 2] 5-Bromo-3-cyano-1H-indole isopropylation screening experiment I

2-lodo Result (HPLC % ratio) Base Solvent Temp. Time Run propane 10 14 min 16 18 min (uv)(equiv) (equiv) (fold) (°C) (h) mm min GD)mm (GD40) min (DO (GD60) Example 1.7 Cs2CO3 Acetone 60 3.0 1.11 N/D 2.17 95.06 1-2-1 (1.7) (5) Example KOH 1.7 r.t 5.0 0.83 18.10 2.55 78.42 1-2-2 (1.7) DMF Example 2.2 KOH (7) r.t 4.0 0.93 11.68 2.86 84.37 1-2-3 (1.7)

Example KOH 1.7 154 7.0 0.43 7.40 1.78 89.75 1-2-4 (1.7) Example KOH Acetone 1.7 60 4.6 1.24 N/D 1.89 95.45 1-2-5 (1.7) (7) GD40:5-Bromo-3-cyano-1H-indole GD60:5-Bromo-3-cyano-1-isopropyl-indole

Through Example 1-2-1, it was confirmed that after completion of the reaction

under the reaction conditions of 5-bromo-3-cyano-1-isopropyl-indole, 5-bromo-3-cyano

1H-indole does not remain. In Examples 1-2-2 to 1-2-4, Cs2CO3 was replaced with

KOH, and the reaction was carried out in a DMF solvent. As a result of changing the

reaction temperature, and the equivalents of 2-iodopropane and KOH, the reaction

proceeded well, but it was confirmed that 0.43 - 0.93% of the starting material (5-bromo

3-cyano-1H-indole) remained. In Example 1-2-5, KOH was used as the base, the

reaction solvent was changed from DMF to acetone, and the reaction was carried out

under reflux conditions. As a result, it was confirmed that results are similar to those

using conventional Cs2CO3. Therefore, it was found that Cs2CO3 can be changed to

KOH. Additional experiments were conducted to verify the results of Tables 1 and 2

above. It was necessary to check the change in the content of de-isopropylated impurity

generated during the work-up process after completion of the reaction and the actual

isolation yield as well as the ratio of conversion to isopropylated product in the 5-bromo

3-cyano-1-isopropyl-indole reaction. The contents of the reactions using 7 types of base

and acetone as a reaction solvent under reflux condition in the following Reaction Scheme

3 are summarized (Table 3).

[Reaction Scheme 3]

CN CN Br 2-lodopropane (1.7 equiv) Br

/ N Acetone (5 fold) N H Base (1.7 equiv) Reflux GD40 GD60

[Table 3] 5-Bromo-3-cyano-1H-indole isopropylation screening experiment II

De-isopropylated Impurity (5-bromo- Gross Net

Run Base Time 3-cyano-1H-indole) HPLC ratio (%) (equiv) (h) Before After After w/up w/up concentration Example Cs2CO3 2.0 0.03 0.16 0.15 96.89 98.65 1-3-1 Example iOH 12.0 15.37 12.76 24.80 99.83 88.41 1-3-2 Example Ca(OH) 2 24.0 99.45 N/A N/A N/A N/A 1-3-3 Example NaOH 5.0 0.83 0.95 0.01 84.54 85.04 1-3-4 Example KOH 3.0 0.12 0.29 0.01 100.97 98.76 1-3-5 Example K2 C0 3 6.0 65.03 N/A N/A N/A N/A 1-3-6 Example NaOAc 6.0 N/A N/A N/A N/A N/A 1-3-7

Example 1-3-1 is an experiment using CS2CO 3 which was used in the

isopropylation reaction, and it was confirmed that de-isopropylated impurity increased

from 0.03% to 0.16% when work up and concentration were performed after completion

of the reaction. In the case of Example 1-3-2, LiOH was used as a base, and after work

up, the organic layer was separated and concentrated, and the sample was analyzed before

proceeding with the crystallization process. As a result, it was confirmed that the de

isopropylated impurity increased from 12.76% to 24.80%. In the experiments using

NaOH and KOH in Examples 1-3-4 and 1-3-5, the tendency of de-isopropylated impurity

to increase during the work up process was also confirmed. Considering the amount of

tarr production in the middle layer generated during work up, reaction time, isolation

yield and base price, it was concluded that it is preferable to use KOH rather than Cs2CO3.

Example 2: Test results of 5-bromo-3-cyano-1-isopropyl-indole crystallization

Example 2.1: Process study for 5-bromo-3-cyano-1-isopropyl-indole

crystallization

As described in Example 1 above, when the de-isopropylated impurity remains

in the process of 5-bromo-3-cyano-1-isopropyl-indole, indole dimer impurity was

generated in the C-N coupling reaction of 1-(3-cyano--isopropyl-indole-5-yl)pyrazole

4-carboxylic acid ethyl ester, but it was not easy to remove in the later manufacturing

process.

[Reaction Scheme 4] Generation of indole dimer impurity by de-isopropylated impurity

CN CN CN Br 2-lodopropane Br Br

N Acetone, Cs2CO3 N - N H Reflux H

GD40 _ GDGO N-dealkylated Impurity

Et0 2C

N N Et0 2C N N N. _

EtO 2C N CN + N

Nm Indoledimer Impurity GD65

GD40: 5-Bromo-3-cyano-1H-indole GD60: 5-Bromo-3-cyano-1-isopropyl-indole GD65: 1-(3-Cyano-1-isopropyl-indol-5-yl)pyrazole-4-carboxylic acid ethyl ester

Specifically, although de-isopropylated impurity was hardly generated during the

reaction, the tendency to increase during work up or in the azetropic distillation process

using ethyl acetate distillation and toluene was confirmed (Table 4).

[Table 4] Generation of de-isopropylated impurity

Result (HPLC % ratio)

Process Step 17.6 min 21.4 min (5-bromo-3-cyano-1H-indole, (5-bromo-3-cyano-1 De-isopropylation Impurity) isopropyl-indole) Final IPC (In nd 100 Process Control)

After Work up 0.538 99.462

After Distillation 3.178 96.822

As a result of tracking the de-isopropylated impurity of 5-bromo-3-cyano-1

isopropyl-indole by HPLC analysis, it was not detected in the reaction IPC (In Process

Control), but was observed to increase during the work up and distillation steps. By

using 5-bromo-3-cyano-1-isopropyl-indole obtained as above, the processes of 1-(3

cyano-1-isopropyl-indol-5-yl)pyrazole-4-carboxylic acid ethyl ester, 1-(3-cyano-1

isopropyl-indol-5-yl)pyrazole-4-carboxylic acid and 1-(3-cyano-1-isopropyl-indol-5

yl)pyrazole-4-carboxylic acid were carried out. Then, the final API (active

pharmaceutical ingredient) was analyzed. As a result, the impurity expected as an

indole dimer was detected, so that the option process was carried out.

Example 2.1.1. Crystallization of 5-bromo-3-cyano-1-isopropyl-indole using i

PrOH

Based on the results obtained by the solubility curve, crystallization of 5-bromo

3-cyano-1-isopropyl-indole using i-PrOH was performed. In the process of

synthesizing 5-bromo-3-cyano-1H-indole using Cs2CO3, 5-bromo-3-cyano-1H-indole is

regenerated by de-isopropylation of 5-bromo-3-cyano-1-isopropyl-indole after layer

separation and participates in 1-(3-cyano-1-isopropyl-indol-5-yl)pyrazole-4-carboxylic

acid ethyl ester reaction to generate indole dimer. In order to search for conditions

capable of inhibiting the generation of indole dimer by removing 5-bromo-3-cyano-1H

indole in advance, after spiking to comprise 0.86%, 1.56% and 3.00% of 5-bromo-3

cyano-1H-indole, they were dissolved under reflux conditions, cooled slowly at room

temperature, kept at 0-5°C for 1 hour, and then filtered. HPLC purity and gross yield of

the obtained crystals were summarized (Table 5).

[Table 5] Residual 5-bromo-3-cyano-1H-indole before and after crystallization of 5

bromo-3-cyano-1-isopropyl-indole using i-PrOH

Result (HPLC %ratio) i-PrOH Time Before After Gross Yield Run (fold) Temp. (h) crystallization crystallization (%) GD40 GD60 GD40 GD60 Example 1.0 Reflux 3 0.86 98.37 0.12 99.68 88 2-1-1 Example 1.0 Reflux 3 1.56 96.83 0.28 99.31 87 2-1-2 Example 1.0 Reflux 3 3.00 94.10 0.59 98.63 81 2-1-3 GD40: 5-Bromo-3-cyano-1H-indole GD60: 5-Bromo-3-cyano-1-isopropyl-indole

As a result of Examples 2-1-1 to 2-1-3, it was confirmed that a small amount of

-bromo-3-cyano-1H-indole, which is de-isopropylated impurity, remained even when crystallization was performed by using 1.0-fold of i-PrOH. When the initial starting material 5-bromo-3-cyano-1H-indole was not sufficiently converted to 5-bromo-3-cyano

1-isopropyl-indole, or the content of 5-bromo-3-cyano-1H-indole was increased by

increasing the de-isopropylated impurity in the work-up process step, it could not be

completely removed even through the crystallization process using 1-fold of i-PrOH was

carried out. Figure 1 is a comparison of HPLC peak areas of residual 5-bromo-3-cyano

1H-indole before and after crystallization of 5-bromo-3-cyano-1-isopropyl-indole.

Example 2.1.2. Crystallization of 5-bromo-3-cyano-1-isopropyl-indole using i

PrOH and anti-solvent (Lab scale)

When crystallization was performed by using i-PrOH, it was confirmed that the

residual 5-bromo-3-cyano-1H-indole was purified, and crystallization conditions were

searched by using anti-solvents to increase the yield. When crystallization was

performed by using i-PrOH, hexane and hetpane, it was confirmed that the residue 5

bromo-3-cyano-1H-indole was effectively removed. There was no significant

difference in the net yield between hexane and heptane (Table 6).

[Table 6] Comparison of residual 5-bromo-3-cyano-1H-indole content before and after

crystallization of 5-bromo-3-cyano-1-isopropyl-indole using anti-solvent

Result (HPLC % ratio) Anti Gross Net i-PrOH Before After Run Solvent Temp. Yield Yield (fold) crystallization crystallization (fold) (%o) (%o) GD40 GD60 GD40 GD60

Example Hexane 1.0 Reflux 0.68 99.32 0.00 99.99 93 90 2-2-1 (2.0)

Example Hexane 1.0 Reflux 1.35 98.65 0.03 99.97 93 91 2-1-2 (2.0)

-1Rx-

Example Hexane 1.0 Reflux 2.59 97.41 0.12 99.88 93 92 2-1-3 (2.0)

Example Heptane Reflux 0.71 99.29 0.02 99.98 94 92 2-1-4 (2.0)

Example Heptane Reflux 1.38 98.62 0.06 99.94 94 92 2-1-5 (2.0)

Example Heptane Reflux 2.54 97.46 0.12 99.88 94 93 2-1-6 (2.0) GD40:5-Bromo-3-cyano-1H-indole GD60:5-Bromo-3-cyano-1-isopropyl-indole

Example 2.1.3. Search for crystallization conditions of 5-bromo-3-cyano-1

isopropyl-indole

Additional tests were performed to determine whether 5-bromo-3-cyano-1H

indole was removed while improving the yield in the crystallization process of 5-bromo

3-cyano-1-isopropyl-indole. After spiking of 0.78% and 2.59%, and crystallization, the

amount of residual 5-bromo-3-cyano-1H-indole was evaluated by HPLC.

When the amount of i-PrOH was reduced, it was confirmed that the yield of 5

bromo-3-cyano-1-isopropyl-indole was improved, but 5-bromo-3-cyano-1H-indole

remained. In view of these results, in order to completely remove the residual 5-bromo

3-cyano-1H-indole, it seemed preferable to proceed with the crystallization under the

condition that 1-fold of i-PrOH is used and 2-fold of heptane is used. However, if

crystallization is carried out in a state in which 5-bromo-3-cyano-1H-indole is present in

an amount of 0.78% or less during the reaction, it was determined that it would be

manageable even if crystallization was performed by using 0.5-fold of i-PrOH (Table 7).

[Table 7] Crystallization condition result of 5-bromo-3-cyano-1-isopropyl-indole through

i-PrOH ratio change

Run i-PrOH Heptane Temp. Result (HPLC % ratio)

- 1 9-

(fold) (fold) Before crystallization After crystallization Gross Yield GD40 GD60 GD40 GD60

Example 1.0 2.0 Reflux 0.71 99.39 0.00 99.99 93 2-3-1

Example - 2.0 Reflux 0.78 99.42 0.68 99.99 95 2-3-2 Example 0.25 2.0 Reflux 0.78 99.42 0.11 99.89 95 2-3-3 Example 0.25 2.0 Reflux 2.59 99.42 0.17 99.83 94 2-3-4

Example 0.50 2.0 Reflux 0.78 97.41 0.04 99.94 94 2-3-5 Example 0.50 2.0 Reflux 2.59 97.41 0.14 99.86 94 2-3-6 GD40: 5-Bromo-3-cyano-1H-indole GD60: 5-Bromo-3-cyano-1-isopropyl-indole

Example 3: Preparation method of 5-bromo-3-cyano-1-isopropyl-indole

Acetone (800 L), 5-bromo-3-cyano-1H-indole (300 kg), KOH (114 kg) and 2

iodopropane (346 kg) were sequentially put into a reactor, and the reaction was carried

out under elevated temperature and reflux conditions. After confirming the completion

of the reaction by HPLC, the reaction mixture was cooled to room temperature. For

extraction and layer separation, EtOAc (1,353 kg) and purified water (1,500 kg) were

additionally added to the reaction mixture, stirred for 1 hour, kept for 1 hour, and the

aqueous layer formed below was discarded. The remaining organic layer was micro

filtrated and concentrated as much as possible by distillation, and residual EtOAc was

checked by GC. After adding 2-propanol (150 L) and heptane (816 kg) to the

concentrated reaction mixture, the temperature was raised to 78°C. When it was

visually confirmed that the reaction mixture was clear, the reaction mixture was

additionally stirred for 30 minutes and then slowly cooled down. Cooling was carried out over about 6 hours, and filtration was performed after keeping at 5-10°C for 1 hour.

The filtered solid was washed with heptane (408 kg) and dried with nitrogen to obtain 5

bromo-3-cyano-1-isopropyl-indole (335.7 kg, 94.0% gross yield).

Example 4: Test results of 1-(3-cyano-1-isopropyl-indol-5-yl)pyrazole-4-carboxylic

acid ethyl ester reaction

Example 4.1. Process study for 1-(3-cyano-1-isopropyl-indol-5-yl)pyrazole-4

carboxylic acid ethyl ester

In the existing preparation process of 1-(3-cyano-1-isopropyl-indol-5

yl)pyrazole-4-carboxylic acid ethyl ester, concentrated crude 5-bromo-3-cyano-1

isopropyl-indole, 1H-pyrazole-4-carboxylic acid ethyl ester, Cul as a catalyst, 1,2

cyclohexanediamine (1,2-CHDA) as a ligand, K2 C3 as a base and toluene as a reaction

solvent were used, and the reaction mixture was stirred for 38-45 hours under reflux

condition, cooled and proceeded to work up using NH 40H and purified water. After

work up, the layer-separated organic layer included excess tar and solid impurities. To

remove these impurities, Na2SO4 and silica gel were added, stirred and then filtered. At

this time, the amount of Na2SO4 and silica gel was used in the same weight ratio as 5

bromo-3-cyano-1-isopropyl-indole, so that a large amount of solid waste was generated

in the filtration process step. The filtrate was transferred to a washed reactor and

concentrated, and after concentration was complete, i-PrOH was added to perform a

crystallization process through temperature increase and cooling to obtain 1-(3-cyano-1

isopropyl-indol-5-yl)pyrazole-4-carboxylic acid ethyl ester. The average yield of the

existing preparation process was about 56%.

[Reaction Scheme 5] Process of 1-(3-cyano-1-isopropyl-indol-5-yl)pyrazole-4

carboxylic acid ethyl ester

EtO 2C N N CN GD10 EtO 2 C XICN Br HN

N Cul, 1,2-CHDA, K 2CO 3 , Toluene / N Reflux Work up: NH 4 0H, PW GD60 Silica gel, Na 2SO 4 GD65 Filtration Crystallization: i-PrOH

GD1: 1H-pyrazole-4-carboxylic acid ethyl ester GD60: 5-Bromo-3-cyano-1-isopropyl-indole GD65: 1-(3-Cyano-1-isopropyl-indol-5-yl)pyrazole-4-carboxylic acid ethyl ester

Example 4.1.1. Ligand screening for 1-(3-cyano-1-isopropyl-indol-5

yl)pyrazole-4-carboxylic acid ethyl ester reaction

As in the above process, in the case of 1-(3-cyano--isopropyl-indol-5

yl)pyrazole-4-carboxylic acid ethyl ester, 1,2-CHDA (1,2-cyclohexanediamine, LI) was

used for the C-N coupling reaction. In this case, it was confirmed that the primary amine

ligand is coupled with 5-bromo-3-cyano-1-isopropyl-indole, resulting in excessive 5

bromo-3-cyano-1-isopropyl-indole-ligand impurity. Eventually, the impurity coupled

with the ligand not only affects the yield, but also delays the completion of the reaction

or the reaction is not completed. In order to solve these problems, ligand screening was

performed first. Ligands used for screening were tested by selecting N-N ligands, N-O

ligands and other applicable ligands (Figure 3).

Ligand screening experimental conditions were as follows: 5-bromo-3-cyano-l

isopropyl-indole (1.0 equiv), 1H-pyrazole-4-carboxylic acid ethyl ester (1.0 equiv),

toluene (4 fold, fold = ml/g of 5-bromo-3-cyano-l-isopropyl-indole), Cul (0.2 equiv),

K 2 C3 (2,0 equiv) and ligand (0.4 equiv) were added and stirred at external set

temperature of 125-130C for 24 hours, and the conversion ratio (%) of 5-bromo-3

cyano-1-isopropyl-indole to 1-(3-cyano-1-isopropyl-indol-5-yl)pyrazole-4-carboxylic acid ethyl ester was used as the evaluation standard (Figure 3).

As can be seen from Figure 3, when the ligand L (1,2-cyclohexanediamine) was

used, the conversion rate was 38.85%, whereas when the ligand L10 (N,N

dimethylethylenediamine, DMEDA) was used, the high conversion rate of 87.28% was

confirmed.

Eventually, if the ligand is changed to L10 at the same reaction time, the reaction

rate is improved and impurity is suppressed, resulting in a higher yield. Except for L2

(1,2-phenanthroline) 0.41% and L7 (JohnPhos) 2.1%, no reaction proceeded at all in the

case of the other ligands.

Example 4.1.2. Base and solvent screening for 1-(3-cyano-1-isopropyl-indol-5

yl)pyrazole-4-carboxylic acid ethyl ester reaction

In Example 4.1.1. it was confirmed the ratio of converting to 1-(3-cyano-1

isopropyl-indol-5-yl)pyrazole-4-carboxylic acid ethyl ester is increased in the case of

using the Li0 ligand rather than the previously used LI ligand. Next, a screening

experiment for the base was performed (Figure 4).

[Table 8]

Solv. HPLC Conversion Ratio (%) Base : Toluene DMF DMSO K2 C0 3 77.60% 62.20% 64.20% K3 P0 4 81.40% 0 67.70% Na t-butoxide 1.0% 37.9% 3.3 %

Cs2CO3 3.70% 75.80% 5.60%

The experimental conditions of Figure 4 were as follows: 5-bromo-3-cyano-1

solvent (4 fold, fold = ml/g of 5-bromo-3-cyano-1-isopropyl-indole), Cul (0.2 equiv), base (2.0 equiv) and 1,2-CHDA (0.4 equiv) were added and stirred at the external set temperature of 125-130°C for 24 hours, and the experiment was conducted with the conversion ratio (%) of 5-bromo-3-cyano-1-isopropyl-indole to 1-(3-cyano-1-isopropyl indol-5-yl)pyrazole-4-carboxylic acid ethyl ester as the evaluation standard. First, as the results of the reactions using K2 C0 3 , K3 P0 4 , Na t-butoxide and Cs2CO3 as a base in toluene solvent, the conversion rates of 77.6% and 81.4% were confirmed in K2 C03 and

K 3 P04 . On the other hand, almost no reaction proceeded with Na t-butoxide and Cs2CO3.

When the reaction solvent was changed to DMF, K 2 CO 3 , Na t-butoxide and Cs2CO3

showed good conversion compared to that using toluene, and K 3 P04 did not react at all.

When DMSO was used, it showed a similar tendency to the experiment using toluene,

but the conversion rate was relatively low. In the above experiments, it was determined

that it is preferable to use K 2 C03 as the base and toluene as the solvent in consideration

of the purchase price of the base and solvent, the safety of the preparation process, and

the latter process (work up and distillation).

Example 4.1.3. Catalyst screening for 1-(3-cyano-1-isopropyl-indol-5

yl)pyrazole-4-carboxylic acid ethyl ester reaction

In Example 4.1.1. and Example 4.1.2., it was determined that the reaction rate

and conversion rate are excellent when N,N-dimethylethylenediamine (L10) is used as a

ligand rather than 1,2-cyclohexanediamine (LI), and K 2 C03 and toluene as the base and

reaction solvent are preferable for 1-(3-cyano-1-isopropyl-indol-5-yl)pyrazole-4

carboxylic acid ethyl ester reaction. Because the synthesis of 1-(3-cyano-1-isopropyl

indol-5-yl)pyrazole-4-carboxylic acid ethyl ester is Ullmann reaction in which a copper

source is used as a catalyst for C-N coupling of1H-pyrazole-4-carboxylic acid ethyl ester

and 5-bromo-3-cyano-1-isopropyl-indole, it was necessary to screen various copper

-?A4- catalysts. In addition, it was necessary to study the cross-coupling reaction of the

Buchwald-Hartwig type using a palladium catalyst. The screening experiments for a

total of four catalysts were performed (Figure 5).

Experimental conditions were as follows: 5-bromo-3-cyano-1-isopropyl-indole

(1.0 equiv), 1H-pyrazole-4-carboxylic acid ethyl ester (1.0 equiv), solvent (4 fold, fold =

ml/ g of 5-bromo-3-cyano-1-isopropyl-indole), catalyst (0.2 equiv), K 2 C03 (2.0 equiv)

and 1,2-CHDA (0.4 equiv) were added and stirred at the external set temperature of 125

130°C for 24 hours, and the experiment was conducted with the conversion ratio (%) of

-bromo-3-cyano-1-isopropyl-indole to 1-(3-cyano-1-isopropyl-indol-5-yl)pyrazole-4

carboxylic acid ethyl ester was used as the evaluation standard.

[Table 9]

HPLC Conversion Ratio Cat. Solv. Toluene DMF DMSO Cul 16.10% 0.70% 32.20% CuBr 14.30% 4.40% 8.1 %

CuCl 8.1 % 27.90% 62.30% Pd(OAc)2 0.0 % 0.0 % 0.0 %

In the case of the catalyst screening experiments, a carousel multi reactor was

used. According to the experimental results, although CuCl showed the highest

conversion ratio of 5-bromo-3-cyano-1-isopropyl-indole to 1-(3-cyano-1-isopropyl

indol-5-yl)pyrazole-4-carboxylic acid ethyl ester under DMSO reaction solvent,

debrominated impurity could be detected by HPLC as a side reaction. Although

Pd(OAc)2 was used as the palladium source, the reaction did not proceed at all in the three

reaction solvents. In the case of Cul, debrominated impurity could be detected when

DMSO solvent was used. As a result, when the reaction was carried out by using CuCl

and Cul in DMSO solvent, the conversion rate of 5-bromo-3-cyano--isopropyl-indole to

1-(3-cyano-1-isopropyl-indol-5-yl)pyrazole-4-carboxylic acid ethyl ester was high, but it

was confirmed that there was a problem that the production amount of debrominated

impurity increased at the same time. Therefore, it was concluded that DMSO solvent

was not suitable for the reaction. Through the above experiments, it was confirmed that

the conversion rate was higher when Cul was used as a catalyst in the toluene reaction

solvent than when CuBr, CuCl, and Pd(OAc)2 were used. Finally, toluene was selected

as the reaction solvent, and Cul was selected as the catalyst.

Example 5: Test result of removing residual Cu in 1-(3-cyano-1-isopropyl-indol-5

yl)pyrazole-4-carboxylic acid ethyl ester

A new approach was needed to improve the 1-(3-cyano-1-isopropyl-indol-5

yl)pyrazole-4-carboxylic acid ethyl ester work up process. Specifically, a new method

in which the adsorption process is omitted and the layer separation can be effectively

performed was considered. Eventually, there was a need to increase the amount of

purified water used to effectively remove Cu-complex, KBr, K2 C0 3 , excess tar and other

by-products, and a method to effectively remove copper by chelating was required. For

this purpose, work up was performed using citric acid and EDTA

(ethylenediaminetetraacetic acid), which are chelating agents.

Example 5.1. 1-(3-Cyano-1-isopropyl-indol-5-yl)pyrazole-4-carboxylic acid

ethyl ester work up study (II)

Example 5.1.1. Work up study (citric acid)

When performing work up after the reaction in the toluene solvent, the organic

layer and the aqueous layer became a turbid lump, and the layers were not separated well,

so after adding ethyl acetate, work up was carried out. Among the various work up methods to replace NH 40H, when 10% citric acid solution was used, the aqueous layer was clean and the layers were separated well, so it was decided to use 10% citric acid solution for the first work up.

Then, after adding purified water, the pH was lowered to 2-3 using 3N HCl to

clearly break the Cu complex. The next step was the treatment with 5% EDTAdisodium

solution to remove the remaining Cu, and this process was repeated once more. Finally,

purified water was added to wash off any remaining salts (Schematic Diagram 1).

[Schematic Diagram 1] Work up conditions using citric acid

Reaction IPC

1twork up PW, EtOAc, 10% Citric acid

Layer separation (disposal of water layer)

2 nd work up H 20, 3N HCl (pH 2~3)

Layer separation (disposal of water layer)

3 rd work up 5% EDTA disodium

Layer separation (disposal of water layer)

4' work up 5% EDTA disodium

Layer separation (disposal of water layer)

5 t' work up H 20

Layer separation (disposal of water layer)

Evaporation

*Each of the solutions was added by 6-fold.

Example 5.1.2. Work up optimization (10% citric acid + HCl)

When the solution used for the first work up was combined with aq. HCl, it was

attempted to find the optimal ratio showing good layer separation behavior (Table 10).

Based on these results, it was determined that the optimal condition is to use 2-fold of 10%

citric acid aqueous solution and 2-fold of 6N HC aqueous solution, respectively, at the

same time, and the appropriate pH range was 2.75 - 3.5.

[Table 10] Conditions and results of the first work up

) Work up Fold HCl Fold Layer separation Run Fl ~ od p solution appearance 10% NH4 Cl Example 5-1-1 aqueous 3 3N 1 8.12 Cloudy aqueous layer 5-1-1 solution 10% NH4 Cl Example 5-1-2 aqueous 2 3N 2 6.94 Cloudy aqueous layer 5-1-2 solution 10% NH4 Cl Example Very cloudy aqueous 513aqueous 5-1-3 souinlayer 1 3N 3 6.85lae solution 10% citric acid Example 514 aqueous 3 3N 1 7.4 Good layer separation 5-1-4 solution 10% NH4 Cl Example aqueous 3 6N 1 8.1 Cloudy aqueous layer 5-1-5 solution 10% citric acid Example Aqueous layer is full aqueous 3 6N 1 8.5 5-1-6 ofbubbles solution 10% NH4 Cl Example Eap aqueous 4 6N 2 8.1 Bad layer separation 5-1-7 solution Example 10% citric acid 4 6N 2 3.5 Good layer separation, 5-1-8 aqueous Easy to distinguish solution color 10% NH4 Cl Example 8 Aqueous layer is full aqueous 8 - - -ofube 5-1-_9b) of bubbles solution 10% citric acid Good layer separation, Example 5-1-10 aqueous 2 6N 2 2.75 Easy to distinguish solution color

Good layer separation, 10% citric acid Example aqueous 2.5 6N 1.5 4.70 Easy to distinguish 5-1-11 . color, Dark organic layer

Good layer separation, 10% citric acid Example aqueous 2.2 6N 1.8 3.72 Easy to distinguish 5-1-12 color, Dark organic layer a) The reaction was carried out on a 10.0 g scale, b) The reaction was carried out on a 100.0 g scale

Then, a scale-up experiment was performed (Table 11). Ina100.0gscaleusing

a 2 L reactor, when 4-fold of 10% aqueous citric acid solution was added, 2.8-fold of 6N

HCl was added, and when 8-fold of 10% citric acid aqueous solution was added, 2.2-fold

of 6N HCl was added, layer separation was good and color distinguishing was easy.

[Table 11] Conditions and results of the first work up

10% Citric Run Scale acid 6N HCl Layer separation appearance

The presence of floating matter in the Exapl 100.0 g 2 fold 2 fold aqueous layer. The color of the aqueous 5-2-1 layerisnotyetchanged to green. The color of the organic layer becomes very Example dark. Layer separation is good, but there is 100.0 g 2 fold 3 fold 5-2-2 floating matter in the aqueous layer in the next step. Example Good layer separation, Easy to distinguish 20.0Og 4 fold 2.8 fold 5-2-3 color Example 20.0 g 8 fold 2.2 fold Good layer separation, Easy to distinguish

5-2-4 color Example Good layer separation, Easy to distinguish 100.0Og 4 fold 2.8 fold 5-2-5 color Example Good layer separation, Easy to distinguish 100.0Og 4 fold 2.5 fold 5-2-6 color

Conventionally, Cu was removed through a process of filtering after adding silica

gel and Na2SO 4 , but a large amount of solid waste was generated in this process, and a

lot of time was required to treat this solid waste. In order to solve this problem, as a

result of conducting various experiments shown in Example 5, a new work up method

was discovered and the filtration process could be replaced with a work up process

utilizing the chelation principle.

Example 6: Preparation of 1-(3-cyano-1-isopropyl-indol-5-yl)pyrazole-4-carboxylic

acid ethyl ester

Toluene (880 L), 5-bromo-3-cyano-1-isopropyl-indole (220 kg), 1H-pyrazole-4

carboxylic acid ethyl ester (129 kg) and K 2 C03 (231 kg) were added to a reactor, and N 2

purge was performed for about 30 minutes. After adding Cul (32 kg) and DMEDA (30

kg), the internal temperature was raised to 45°C while maintaining the N 2 purge. After

9 hours of reaction under reflux condition, reaction IPC (in process control) was

performed to confirm the completion of the reaction, and the reaction mixture was cooled

to room temperature. The reaction time of 35 hours in the existing process was reduced

to 9 hours. For extraction and layer separation, 10% aqueous citric acid solution (880

L) and EtOAc (794 kg) were sequentially added to the reaction mixture, and then 6 N

HCl (381 kg) was added dropwise to adjust pH = 2-3. After stirring for 30 minutes, the

resulting product was allowed to stand for 1 hour, and the separated aqueous layer was

discarded. After adding 5% EDTA aqueous solution (880 L) to the remaining organic layer, it was stirred for 30 minutes and allowed to stand for 1 hour to proceed with layer separation. The same process was repeated twice in total. Finally, after adding purified water (880 L), the aqueous layer separated by stirring and standing for 30 minutes was discarded. In the above processes, the extraction and layer separation were performed a total of 4 times at about 35°C. The remaining organic layer was distilled as much as possible after microfiltration, and concentrated IPC (in process control) was performed to confirm that EtOAc was removed. After the distillation was completed,

2-propanol (880 L) was added to the reaction mixture, and then the temperature was raised.

When it was confirmed that the reaction mixture was clear, it was cooled slowly to 0

°C for 7-8 hours, kept for about 1 hour and filtered. The filtered solid was washed

with 2-propanol (880 L) and dried using nitrogen and vacuum to obtain 1-(3-cyano-1

isopropyl-indol-5-yl)pyrazole-4-carboxylic acid ethyl ester (253.5 kg, 94.0% gross yield).

This is about 1.7 times higher than 56% yield of the existing process.

Claims

1. A method for preparing a compound of the following Formula 2, comprising:

i) a step of reacting a compound of Formula 1 and X-R3 with a base comprising

KOH in an organic solvent; and

anti-solvent comprising hydrocarbon having 5 to 8 carbon atoms:

[Formula 1]

R1

XN N \R2

H

[Formula 2]

R1 X

R3

wherein,

X is F, Cl, Br or I;

R1 is hydrogen or CN;

R2 is hydrogen, halogen, C1 -C 7 alkyl, C1 -C 7 alkoxy-Ci-C 7 alkyl or phenyl; and

R3 is hydrogen; CI-C 7 alkyl unsubstituted or substituted by one or more

w

R7 ,wherein R6is C1-C4 alkyl, WisOor S,R7 is hydrogen or C1-C4 alkyl, and n is an integer of 0 to 3.

2. The method according to Claim 1, wherein X-R3 is 2-iodopropane.

3. The method according to Claim 1, wherein the organic solvent is acetone.

4. The method according to Claim 1, wherein the alcohol is one or more selected

from the group consisting of methanol, ethanol, propanol, isopropanol and butanol.

5. The method according to Claim 1, wherein the hydrocarbon having 5 to 8 carbon

atoms is selected from the group consisting of hexane, heptane and a mixture thereof.

6. A method for preparing a compound of the following Formula 4, comprising:

a step of carrying out a C-N coupling reaction of a compound of Formula 2 and

dimethylethylenediamine in an organic solvent:

[Formula 2]

R1

X K\R2

R3

[Formula 3]

R4 N R5 \N

NH

[Formula 4]

R4

R5 I R1 N

R3

wherein,

X is F, Cl, Br or I;

RI is hydrogen or CN;

R2 is hydrogen, halogen, C1 -C 7 alkyl, C1 -C 7 alkoxy-C1-C7 alkyl or phenyl;

R3 is hydrogen; CI-C 7 alkyl unsubstituted or substituted by one or more

W R7 , wherein R6 is CI-C4 alkyl, W is 0 or S, R7 is hydrogen or C1-C4 alkyl,

and n is an integer of 0 to 3;

R4 is hydrogen, halogen or C1 -C 7 alkyl; and

R5 is -C(O)OR8, wherein R8 is hydrogen, C1-C 7 alkyl or C 3 -C 7 cycloalkyl.

7. The method according to Claim 6, wherein the organic solvent is one or more

selected from the group consisting of xylene, toluene, dimethylformamide (DMF) and

dimethyl sulfoxide (DMSO).

8. The method according to Claim 6, wherein the copper catalyst is one or more

selected from the group consisting of Cu, Cu(OAc)2, Cu, Cu20 and CuO.

-1 4-

9. The method according to Claim 6, wherein the base is one or more selected from

the group consisting of potassium carbonate, cesium carbonate, potassium phosphate

tribasic, triethylamine and sodium tert-butoxide.

10. The method according to Claim 6, which further comprises a step of purifying

the compound of Formula 4 by using:

one or more chelating agents selected from the group consisting of EDTA, citric

acid, potassium citrate and sodium citrate; and

one or more ligand reagents selected from the group consisting of ammonium

chloride and aqueous ammonia.

11. The method according to any one of Claims 1 to 5, wherein RI is CN, R2 is

hydrogen, and R3 is isopropyl.

12. The method according to any one of Claims 6 to 10, wherein RI is CN, R2 is

hydrogen, R3 is isopropyl, R4 is hydrogen, and R5 is ethoxycarbonyl (-C(O)OEt).

[Figure 1]

GD40 before crystallization GD40 after crystallization

4.00

3.00 3.00

2,00

1.56

1.00 0.86 0,59 0.28 0.12 0,00 X 1 2 3

[Figure 2]

OH OH NH2 O OH N N OH L1 NH2 N L2 N L3 L4 L5

IN O O H O N N OH NH P OH L6 L7 L8 L9 L10

- 1/3 - - 1/3 -

[Figure 3]

100

80

60

40

20

o L1 L2 L3 L4 L5 L6 L7 L8 L9 L10

[Figure 4]

100 100

80 80

60 60

40 40

20 20 DMSO DMSO 0 0 DMF DMF K2CO3 K2CO3 Toluene Toluene K3PO4 K3PO4 Na t- Na t- Cs2CO3 Cs2CO3 butoxide butoxide

2/3 -- - 2/3

[Figure 5]

70 70

60 60

50 50

40 40

30 30

20 20

10 10 DMSO DMSO 0 0 DMF DMF CuI Cul Toluene CuBr Toluene CuBr CuCl CuCl Pd(OAc)2 Pd(OAc)2

- 3/3 - - 3/3 -